Compressor Not Starting - Buzzing

[pelletman]

Good Afternoon
My dad's compressor is an old Champion, 5HP 240V Single phase with a magnetic starter. Sometimes (often I would say) the compressor will try to start and it sounds like the starter is pulling in and it just buzzes, if you turn it off and on with the pressure switch switch it will start. It seems like it is worse in the cold and I think the problem is getting progressively worse. I realize start capacitors could cause this problem also, and my dad says that one of the start capacitors (at least) was replaced in the past, and they don't show any signs of physical failure, but it is the magnetic starter that is making the noise, and I just wanted to get some guidance here. If it is the starter (picture attached) can I clean or repair it (points?), replace the relays, or do I need to replace it? If I replace it should I go with an American unit for probably 300 bucks or the Chinese one for $60? Thanks for your input!

 

[pelletman]

More info on the compressor in this post:

Show Your Vintage Compressors

I have one more old compressor!! I got it earlier this year to run my sand blasting box It is a flat head 4 cylinder air compressor and a 4 cylinder gas motor combination

www.garagejournal.com

 

[pelletman]

Wow, after looking more closely at the relay I see a burnt contact, second from left with the red wire hooked up to it

 

[pblanton]

90% of the time a failure to start / buzzing / humming until it trips the breaker is a bad capacitor. I'd replace that (those) first before worrying about the switch.

The capacitors are cheap and do wear out, so if you replace them, it still doesn't work, and you end up needing to replace the switch, then you won't be out too much money.

The fact that tripping the pressure switch off and on starts it, does lend some credence to the idea that the switch is bad. Generally the Chinese switches are cheaper because they are coming straight from the manufacturer and not because they are junk. Your mileage may vary, but I'd go with the Chinese version. If it works out of the box, it'll probably work forever.

$300 for an air compressor pressure switch is crazy. $60 seems about right. The good Ingersoll Rand and Square D pressure switches are about $135 locally; at Ace Hardware, which is an expensive place to buy things. Hubbell is a great brand, and theirs with the integrated unloader is $55 on Amazon.

https://www.amazon.com/dp/B00273SR58/?tag=atomicindus08-20

Note: I can't include the URL without the "atomicindus" tag. I presume that turns it into an affiliate link for Garage Journal.

At that price, I'd replace the capacitors and the pressure switch.

Update: While I was writing this you posted that you have a burnt contact on the pressure switch. So I'd definitely replace that. I'd also replace the caps too because they are cheap and do wear out. You can probably replace it all for $90.

While you're at it, I'd do the full service. New air filters, and a new oil change. Check the belts too while you're at it.[/URL]

 

[pelletman]

To continue this conversation with myself, the starter I have is a NEMA Size 0 and the parts are available to repair the burnt contactor. That is the direction I will go. I found the correct part number on ebay in NOS stuff.

 

[pelletman]

Thanks! I appreciate the input. I did change the oil a couple days ago. I will start with fixing the contactors and go from there.

 

[RPH]

Move wire on L1 to L2, likewise on motor wires. Clean the contacts of carbon and check the relay core for **** that doesn’t let it settle into it. Buzzing usually means core is vibrating.

 

[pelletman]

90% of the time a failure to start / buzzing / humming until it trips the breaker is a bad capacitor. I'd replace that (those) first before worrying about the switch.

The capacitors are cheap and do wear out, so if you replace them, it still doesn't work, and you end up needing to replace the switch, then you won't be out too much money.

The fact that tripping the pressure switch off and on starts it, does lend some credence to the idea that the switch is bad. Generally the Chinese switches are cheaper because they are coming straight from the manufacturer and not because they are junk. Your mileage may vary, but I'd go with the Chinese version. If it works out of the box, it'll probably work forever.

$300 for an air compressor pressure switch is crazy. $60 seems about right. The good Ingersoll Rand and Square D pressure switches are about $135 locally; at Ace Hardware, which is an expensive place to buy things. Hubbell is a great brand, and theirs with the integrated unloader is $55 on Amazon.

https://www.amazon.com/dp/B00273SR58/?tag=atomicindus08-20

Note: I can't include the URL without the "atomicindus" tag. I presume that turns it into an affiliate link for Garage Journal.

At that price, I'd replace the capacitors and the pressure switch.

Update: While I was writing this you posted that you have a burnt contact on the pressure switch. So I'd definitely replace that. I'd also replace the caps too because they are cheap and do wear out. You can probably replace it all for $90.

While you're at it, I'd do the full service. New air filters, and a new oil change. Check the belts too while you're at it.[/URL]

Yeah, I see what you are saying, but it is the magnetic starter that seems to be the problem, NOT the pressure switch, which is brand new as the compressor wouldn't shut off a few days ago. Now I am questioning if the switch was the actual problem, but it seemed to take care of the problem. Like this magnetic starter but WAAAYYYY older

https://schulzproducts.com/product/square-d-motor-starter-5hp-1-phase-230vac-30-amp/

 

[pblanton]

I have the 80 gallon Champion compressor too. Mine came with a 3-phase motor and I replaced it with a 5HP single-phase Baldor motor and a new magnetic starter box. It's been working fine for five years. I bought the Lefoo pressure switch with unloader but my compressor didn't need the unloader on the switch.

Fresh Pics...

 

[pelletman]

Move wire on L1 to L2, likewise on motor wires. Clean the contacts of carbon and check the relay core for **** that doesn’t let it settle into it. Buzzing usually means core is vibrating.

So move the L1 black wire to L2 and then move the red wire right under it to L2 just bypassing all of L1? That seems like a good idea, and cheap solution to the problem! Thanks!

 

[pelletman]

I have the 80 gallon Champion compressor too. Mine came with a 3-phase motor and I replaced it with a 5HP single-phase Baldor motor and a new magnetic starter box. It's been working fine for five years. I bought the Lefoo pressure switch with unloader but my compressor didn't need the unloader on the switch.

Fresh Pics...

I have access to a nice and free 7.5 HP champion that is about 5 years old, but it is 3 phase and I would have to change the motor, I just haven't gotten around to it yet. Too many projects on the list!

 

[TurnipTruck]

BLUE:it looks like the “heater” overload has opened and been bypassed. If you buy a new starter you will specify a heater just above the motor FLA (full load amp draw)
RED: on the industrial starters I am accustomed to, these screws allow the contacts to come out for inspection/cleaning/replacement, but that may not apply to this light duty starter.
YELLOW: these screws may allow you to access the contacts instead. The contacts are usually silver-coated copper and look like smooth buttons, but I’m guessing yours don’t.

Noise is typically dirt between the magnetic halves not allowing full flux transfer and buzzing at 60 hertz. If blowing out with air doesn’t quiet it, time for new.

 

[pblanton]

I have access to a nice and free 7.5 HP champion that is about 5 years old, but it is 3 phase and I would have to change the motor, I just haven't gotten around to it yet. Too many projects on the list!

Ooohhh You gotta snag that! The motor will be about $350 to replace and you'll need a new magnetic starter for it. I still have the 3-phase motor that came off of mine. Apparently they are pretty hard to sell. I imagine that people who need a nice used 3-phase motor are a pretty small group.

This is the starter on my 5HP 80 gallon Champion. https://www.amazon.com/dp/B0CKXRDCF8/?tag=atomicindus08-20 It's been working flawlessly for 5 years.

 

[pelletman]

Ooohhh You gotta snag that! The motor will be about $350 to replace and you'll need a new magnetic starter for it. I still have the 3-phase motor that came off of mine. Apparently they are pretty hard to sell. I imagine that people who need a nice used 3-phase motor are a pretty small group.

This is the starter on my 5HP 80 gallon Champion. https://www.amazon.com/dp/B0CKXRDCF8/?tag=atomicindus08-20 It's been working flawlessly for 5 years.

Well, if I want a 7.5 HP 1PH motor I see them more around $1000

 

[pelletman]

Looks like the other issue I have is that this starter is max rated for 2 HP at 220V single phase and I have a 5HP motor

 

[Bert_]

Looks like the other issue I have is that this starter is max rated for 2 HP at 220V single phase and I have a 5HP motor

I was just about to post that! Yes size 0 is 2hp at 240 volt. You would need a size 2 for 5 hp. You could also use an IEC style starter. They aren't as robust as a NEMA style but are less expensive.

 

[pelletman]

I was just about to post that! Yes size 0 is 2hp at 240 volt. You would need a size 2 for 5 hp. You could also use an IEC style starter. They aren't as robust as a NEMA style but are less expensive.

Thanks! I have an Eaton I can grab off a 7.5 HP compressor which I plan on putting in place here sometime in the future. It is presently 3 phase but I can use it on single from what I have seen. This compressor has probably been running with this little starter for 30 years or so.

 

[pelletman]

OK I moved everything out of the way, so I could see the top of this, changed the contactor from L2 to L1 (I had changed the 120V wire on left to L2 along with the red one below it, but that didn't work, so I swapped the contactor. I have no idea where this red wire on top came from, the only think I took off was L1 to move it to L2 so I am thinking it was hooked to L1 but I am not sure. The other end goes to T2 (i have to confirm that) is this the jumper wire to use a 3 phase starter in a single phase situation? Should it be hooked to L1?

Thanks again for all the input here.

 

[pelletman]

Ooohhh You gotta snag that! The motor will be about $350 to replace and you'll need a new magnetic starter for it. I still have the 3-phase motor that came off of mine. Apparently they are pretty hard to sell. I imagine that people who need a nice used 3-phase motor are a pretty small group.

This is the starter on my 5HP 80 gallon Champion. https://www.amazon.com/dp/B0CKXRDCF8/?tag=atomicindus08-20 It's been working flawlessly for 5 years.

You sure that is the one you have? That is for 3HP

 

[TurnipTruck]

I found this picture on here a year ago and saved it. My own starter did not require all three phases to be used like this one does.

 

[pelletman]

Correction, that red wire goes to T1 on the other end

 

[metalmagpie]

If you want to really do a proper maintenance job on that Champion, pull off the valve manifolds and take out the valves and take them apart and clean and lap the plates and put the valves back with new crush washers. Pay attention to whether the copper or aluminum crush washer is on top.

Valves need attention every few years.

I looked at the pix from the post you linked. It is actually not hard to straighten fins on intercooler tubes. Just take two small screwdrivers and a small pair of pliers and one at a time bend the fins back into shape. The fin metal is almost pure aluminum, very ductile. I did two very damaged intercoolers on my recent Champion rebuild and not one of the fins broke off. I just spray painted them afterwards with automotive primer. Brush painting them seemed to me to be impractical.

metalmagpie

 

[pelletman]

If you want to really do a proper maintenance job on that Champion, pull off the valve manifolds and take out the valves and take them apart and clean and lap the plates and put the valves back with new crush washers. Pay attention to whether the copper or aluminum crush washer is on top.

Valves need attention every few years.

I looked at the pix from the post you linked. It is actually not hard to straighten fins on intercooler tubes. Just take two small screwdrivers and a small pair of pliers and one at a time bend the fins back into shape. The fin metal is almost pure aluminum, very ductile. I did two very damaged intercoolers on my recent Champion rebuild and not one of the fins broke off. I just spray painted them afterwards with automotive primer. Brush painting them seemed to me to be impractical.

metalmagpie

Thank you!